1. Field of the Invention
The present invention relates to an inner-rotor-type motor and, more particularly, to an inner-rotor-type motor with a bearing seat.
2. Description of the Related Art
FIG. 1 shows a conventional inner-rotor-type motor 8 having a bottom for a bearing seat 9 to mount on. The inner-rotor-type motor 8 substantially includes a housing 81, a stator 82 and a rotor 83. The housing 81 has a compartment 810, an upper opening 811 and a lower opening 812. The upper opening 811 and the lower opening 812 communicate with the top and bottom of the compartment 810 respectively. The stator 82 with a through-hole 821 is mounted in the compartment 810. The through-hole 821 has two ends in the form of openings communicating with the upper opening 811 and the lower opening 812 in alignment. The rotor 83 has a shaft 831 arranged along an axle thereof. The rotor 83 is rotatably coupled to housing 81 through the bearing 84, with the shaft 831 being received in the through-hole 821 of the stator 82 and extending through the upper opening 811.
Referring to FIG. 2, the bearing seat 9 is mounted in the lower opening 812 of the housing 81. The bearing seat 9 includes a socket 91 and a base 92. The socket 91 is coupled to the lower opening 812 of the housing 81. The socket 91 has a first recess 911, a second recess 912 and a plurality of apertures 913. The first recess 911 is formed on a side of the second recess 912 and communicating with the second recess 912, with the inner diameter of the first recess 911 being smaller than that of the second recess 912. The first recess 911 is for receiving the bearing 84, and the second recess 912 is for receiving a circuit board 85. Moreover, the first recess 911 forms an opening 914 on a top of the socket 91, and the second recess 912 forms an opening 915 on a bottom of the socket 91. The shaft 831 has an end extending through the opening 914 into the first recess 911 and coupling to the bearing 84 received in the first recess 911. The apertures 913 are formed on the top of the socket 91, communicate with the second recess 912 for wires of the stator 82 to extend through the apertures 913 into the second recess 912, and are electrically connected to the circuit board 85. The base 92 covers the opening 915 on the bottom of the socket 91 in alignment.
In general, for preventing the bearing 84 in the first recess 911 from falling into the through-hole 821 of the stator 82, the opening 914 on the top of the bearing seat 9 narrows inwards to form a shoulder 916 for cooperating with a fastener 86 to restrict the bearing 84 in the first recess 911. However, forming the shoulder 916 decreases the inner diameter of the opening 914, so the bearing 84 and circuit board 85 in the first recess 911 and the second recess 912 can be arranged only by sequentially passing through the opening 915 on the bottom of the socket 91. Besides, the apertures 913 are formed on the top of the socket 91, so the wires need to pass through the apertures 913 for entering the second recess 912, thus causes causing assembly inconvenience.
With the trend toward miniaturization of the motor sizes, the conventional inner-rotor-type motor diminishes accordingly and the first recess 911 is barely enough to receive the bearing 84, so mounting the fastener 86 on the end of the shaft 831 in the first recess 911 is not easy in assembly, thus increasing the assembly difficulties. Hence, there is a need for an improvement over the conventional inner-rotor-type motor.